A Sample of a Structured Reponse to ESGAA Comments

A sample of a structured response to Grant Review Board (GRB)/ Referees’ comments

GRB

GRB1: This study presents a comparison of respiratory symptoms of children in two districts of Hong Kong before and after institution of reductions in sulphur levels in fuel. The design is elegant and would provide important information. The collection and analyses of the respiratory symptom data are appropriate. Unfortunately, the presentation of these analyses are inadequate, and the results are over-interpreted.

A:The paper has been extensively revised and rewritten and the amount of information from the analyses reduced. In particular the cross-sectional analysis has been deleted. We have attempted to improve the presentation of the analyses from the follow-up cohort and exercised greater caution in the interpretation of results.

Referee I

RI(1): First, no quantitative air pollution measurements are provided. This study is based on the premise that the fuel intervention reduced air pollution concentrations in Kwai Tsing District much more than in the Southern District. However, there is no evidence presented to justify this. Hong Kong Government reports are cited, but these reports are not available to this reader, and I expect not available to most readers of the journal. Such a lack of basic exposure data is unacceptable. (The authors never specify what the sulphur reduction was in the intervention.) At a minimum, the authors should specify SO2, particle, and NO2 mean concentrations for each district, for the periods before and after the fuel intervention.

A:We have tabulated all of the relevant and available air pollution data with particular emphasis on SO2 and sulphate concentrations in respirable particulates which were most affected by the restrictions on the sulphur content of fuels. The observed values for the period of the field study are included together with the annual means (see Table 1).

RI(2): Secondly, the authors present no prevalence data for any of the symptoms. This paper would be substantially improved with a tabulation of reporting rates by district and by period to provide the reader with a basis for evaluating the effect estimates.

A:We have tabulated the reporting rates of grouped symptoms by district and year of study to demonstrate the trend in between district differences.

Referee II

RII(1):The use of factor analysis is appropriate. However, the ultimate classification of symptoms into four categories is consistent with our priors. The tabulation of results both for the symptom groups (OR) and for factor scores (regression coefficients) is repetitive and adds little to the presentation.

A:We have deleted the data on regression coefficients from analysis of factor scores. The analyses are now based only on the binary variables (formed from identification of groups of correlated symptoms in the factor analysis) which were used in the logistic regression. The binary variables were defined as having or not having any of the symptoms in the group. We have presented the between district differences in the within-district changes over the three years.